A parcel conveyor operates with a constant total input power of 2500 W. Energy passes through two stages before being transferred usefully to the parcels. The output power from the electronic controller is the total input power to the belt mechanism.
| stage | efficiency |
|---|---|
| electronic controller | 0.90 |
| belt mechanism | 0.80 |
The conveyor operates for 3.0 minutes3.0\ \mathrm{minutes}3.0 minutes.
Calculate the useful energy transferred to the parcels during this time.